Gas process.



F. P. PETERSON.

III PROCESS. APPLICATION FILED IAN. 5. 19M. ENEWED IAN. 2s. i918. Lk Patented May 2l, 1918.

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F. P. PETERSON.

GAS PROCESS. APPLICATION flu-D JAN. 5. 1914. RENEWED 11111.26. 1918.

a 11. Patented May 21,1918.

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FRANKLIN PIERCE PETERSON, OF TULSA, OKLAHOMA, ASSIGNOB. T0 CONSOLIDATED LIQUID GAS COMPANY, OF CHICAGO, ILLINOIS, A. CORPORATION OF ARIZONA.A

Patented May 2i, i938..

Application led January 5, 1914, Serial No. 810,332. Renewed January 26, 1918. Serial No. 214,035.

To all whom t may concern:

Be it known that I. FRANKLIN I). PETER- sox, at'Tulsa, in the county of Tulsa and State of Oklahoma, have invented a new and useful Improvement in Gas Processes, of which the following is a specification.

This invention relates to a process for separating out of crude gas, such as for in stance oil well gas, some or all of its liquefiable constituents.

In a prior Patent No. 1,031,664, of July 2, 1912, issued to me, I have disclosed 4a process Jtor obtaining, `direct from natural gas, a liquefied gaseous product adapted for commercial use. The present invention concerns a develolmuentv andan improvement of the process disclosed in my former patent; Natural gas contains, in addition 'to some other compounds, methane, thane, propane, butane, pentane and hexane. Of these pentane and hexane are liquids at ordinary temperatures and atmospheric pressure. Butane, propane and ethane are gaseous under normal conditions of temperature and pressure, but may be liquefied and maintained as liquids at moderate pressures and normal temperatures. Methane cannot exist as a liquid at normal temperature: it is known as a so-called permanent gas.

The pressure required to produce a liquid condensate from any gas, as Well as the nature of the condensate, depends both upon the substances in the gas and upon their proportions. For instance, from a gas containing propane and ethane, `if the proportion of propane is large as compared with ethane, a mixture rich in propane may be obtained with a comparativelyylow pressure. If, however, thev proportion of propane is small as compared with ethane, a considerably higher pressure will be required to liquey propane and the condensate .se-

cured will contain a larger proportion ot ethane. When mixtures of twoy or more gases are involved, enough pressure will frequently have to be applied to bring down a considerable proportion of l the higher stage product before it is possible to secure the lower stage product'. Itis desirable, however, to secure these liquid products as pure as possible and to place them on the market at as low pressures as possible.y In ust referred to, using a citizen of the United States, residing l constituents.

ethane and propane as an illustration, the vapor pressure of the liquid product containing propane and ethane would be considerabl y higher than that required to hold propane alone in liquid form.

. The process disclosed in my former patent contemplated the removal from natural gas of its liquefiable constituents by compressing and cooling the gas, in stages. In carryingv out the process, through a low stage compression and cooled, which removed as liquids its least volatile It then passes on to other successive higher pressure stages of the process whereby its other liqueable constituents were successively removed in an order inverse to that of their volatility. The product obtained from 'eachstage of the process was drawn oli' into a separate container.

The present invention concerns the saine general process but includes a method whereby the contents of each container may be positively and definitely standardized. That is to say, bythe application of the method herein disclosed the vapor pressure in each container used to receive the several .products of 4the process may be definitely determined independent of 'the pressure at which the liquid sent to that container was precipitated. Thus I may use a comparatively high pressure in bringing down the liquid condensate, but I thereafter treat the cndensate in such a fashion that its vapor pressure is caused not to` lexceedwa certain definite maximum for a certain delinite temperature. which vapor pressure may be considerably lower than the pressure at which the liquid was condensed. Moreover I bring about this result without wasting any particle of the liquefiable constituents of the gas. All liquefiable gaseous constituents which are too volatile to be confinable under the conditions which I set for the product in any container are -returned to the process and recovered as liquids at some other l,stage thereof. My invention contemplates, objects, stituents of natural gas in a much purer form than has hitherto been possible. vAnother object of my invention is to subject each liquefied product obtained in the as one of its the gas carried the obtaining of the several conprocess to definite temperature and pressure conditions and to allow the escape from the bulk of the liquid of any of its constituents v obtain as liquefied gases all the liquefiablel constituents of the natural gas which are liquefiableat normal temperature and to allow no portion oi the liquefiable part of the gas to escape along with the permanent gases (such as methane) which are discharged at the end of the process.

In the drawings Figure '1 is a diagrammatic representation of my process.

Figs. 2 and 3 are modifications thereof. v`

In the drawings of my processv is shown as embodied in four stages, I, II, III and 1V; it being of course understo d that either more or fewer stages could e used in the process if found necessary or desirable. The supply pipe 5 leads the crude gas to the process from the source of its origin, such as4 an oil Well.

From the pipe 5 the gas goes to compressor 1 wherein it is compressed at a low stage, issuing from the compressor through the pipe 9. It then passes through the cooling device 13, which may be of any form desired (these appliances being well known in the art) and enters the cooler 21. This cooler comprises a central chamber 21', two head spaces at the ends of the central chamber, and a plurality of tubes 22 connecting the head spaces. Underv lthe compression and cooling to which the gas is bein -subjected, a portion thereof will be con ensed as a liquid in the cooler 21. This liquid drains 0H' through the pipe 23 into the collecting tank 24 whence it o-ws into the trap 26. The trap 26 periodically discharges through the pipe 27 and the reducing valve 28, into the lower head space of the cooler.

lnasmuch as product so separated out has been reduced by the reducing valve 28, a certain portion of the liquid will Volatilize andw` pass up through the tubes 22, the remainder of the. -liquid passing off through pipe 29 into the first container 30. The volatili-zation and expansion of the gas in the cooler 21 will cool the gas passing 9, as'will readily be understood byV those familiar with the art. The gases passing up through the pipes 22, in the modification disclosed in Fig. 1,. next pass through a regating valve and are discharged into. the supply pipe 5.

-In the modification shown in.Fig'. 3, the gases passing'through tubes22 in the cooler are led into a small auxiliary com lressor 20 and therefrom into the e 6. us arrangement av'oids the possiiiiiity of having the. pressure in theliquid thereinto from the pipe" these gases condense again in:` thel first stage of compression and cooling as shown in Fig. 1.

The method-,here shownl as employedin the first stage of the process, may' be employed in a higher stage, inwhich case the 'gases emerging from the tubes 22 of the cooler could be led into any one of the lower stages of the process as illustrated in Fig. 2 wherein the gases. are led .from cooler 22 through pipe 17 and regulator 18 to discharge into another sta-ge as shown at 19.v

It will be apparent that the. liquid condensate incontainer30, has been ridl of all 'practically all. the more volatile conrlensates'wh-ichl may have been brought down in the first stage compression` Front thef-rst stag passes through. the. pipe 6 into-the. second compressor 2- where.l it is compressed at a higher pressure. Emerging. from. the second compressor 2 itpassesthro'ngh a cooler 14 and theirJ into. a settling chamber 31. The liquid product precipitated in. chamberv 3l is drawn therefrom through pipe 32 into. a collecting tank whence. it. Hows t i e 34 intothe trap 35 whence pe cally discharged through P PoB into. container 3.7. A pipe 38 communicates from container 37 toa1 small au compressor 39v whose outlet discharges, t rough pipe 40V into pipe 7., the discharge. pipe for the second stage of the rocess. as clearly seen in the drawings.A e pressure in the container 37 is thus maintained. at. a. prede.- termined value by meansl of the auxiliary arising in containerY 3 .discharges t 'ein into the succeeding stage of'tli'epraccss. In this way, the product. in container 3T is standardized, its vapor pressure definitely determined, the liquid is again t in a form suitable for market, the-cooling effect of thevaporization is availed.' of'to reduce the power required for the compression in compressor 39 and the vapors are discharged into the next higher stage of the process, whicheliminates the possibility of their beino', condensed again in the same stage. 'Y

he.' residue from thesecon stage passes through pi e 7' into.v compressor 3 vc'hence it' passes t rou h cooler 15 into a settlin chamber 41; e liquid condensed in. sett iii chamber 4:1 is led through U-pipe 42throug a heater 43 and into a collecting tank 45'.. The heater 43 serves to drive oif e of-,my process thegas froni'the condensate brought down in the passes through a cooler 48 into a trap t9 whence it is periodically discharged through pipe 50 into a third container 51. By this method the .most rebellious constitutents of the liquefied product are driven o'by heat and the vapor pressure of the product is reduced so that the pressure in container 51 is less than that of compressor 3, whereby again the liquid product is standardized as to vapor pressure and made suitable for commercial handling.

The residue gas from this stage of the processl passes through pipe 8 into compressor -I whence it is passed through cooler 16 into the settling chamber 52. The liquid deposited in chamber 52 passes into a collecting tank 57 whence it flows through pipe 58 into a trap 59, which periodically discharges through pipe 60 into the container container 61 is in communication, through the pipe 62 and regulating valve 63, with the pipe 64. The pipe 64 may be connectedas indicated at 65, 66, 67 and 68, either with.

the discharge pipe of the gases from the fourth stage o the compressor or with any stage of the process; thus the vapors unconnable in container 61 under the conditions of temperature and pressure prescribed for that container, may be passed back into the process for retreatment or may be carried off with the'unliqueable permanent gases, or introduced to a process. l

The residue gas from the fourth stage passes through the regulating valve 54 out throughthe Itube 55 to. be used either for cooling in the various stages of the process or for use in other portions of the plant. It the method here disclosed in the fourth stage were not applied to the last stage of the process,the residue gas from settling chamber 52 rectly into a higher stage.

lVhile I have shown'diderent treatments for each stage, I wish it to be clearly understood that any one of these treatments might be introduced at any stage ofthe process. It is obvious that this process is not limited to four stages; either a greater or less number of stages may be used according to the composition of the crude gas and the number` of products desired.

61. The

sure, cooling higher stage of theV would pass through pipe 53 dif Inasmuch as the condensate at each stage ot' the-process is subjected t'odefinitc temperature. and pressure conditions and .the gases uriconnable under those conditions `are allowed to escape from the bulk of the condensate, I obtain a standardized product for each stage, that is one, substantially all of which is of thcI same vapor pressure, and

in many cases I obtain a substantially purcf product.

1. The process of separating from crude gas its liqueable constituents by liquetying constituents of the gas in the inverse order of their volatility, collecting the product of each stage of liquefaction separately and subjecting the separate products to predetermined and varying temperature and pressure conditions to allow the escape from'each thereof of gases only liquefiable at a higher stage.

'2. The process of separating out a plurality of liquefia'ble gases from crude gas which consists in liquefying constituents in the' gas in a. plurality of stages in the inverse order of their volatility, subjecting the liquid product from each stage to definite temperature and pressure conditionsand returning to the gases which are unconfinable at the temperature and pressureA applied to each liquid to the unliquefied gases for further treatment.

3. The method of removing liquefiable constituents from' a crude gas which consists in compressing the gas to a low presthe compressed gas, drawing oft' the liqueed product into a container, and pumping oft' the vapors from said container into the intake of a higher stage compressor.

4. The method of separating out the liquefiable constituents of natural gas in stages which consists in compressing the gas to a low pressure, cooling it then compressing it to a higher pressure, drawing the liquefied product of the first' compression into acontainer and allowing the vapors Jfrom the container to expand against resistance and discharging them into the intake ofthe higher stage compressor.

5. The method of separating out the liqueiable constituents of natural gas in stages which consists in compressing the gas to a lowr pressure, cooling it then compressing it to a higher pressure, drawing the liquefied product-of the first compression into a container, maintaining the pressure in the container at a denite pressure and allowing gases in the container unconnable at such pressure to enter a higher stage of compression, p Y v 6. The method of producing a liquefied the liqueiedrproduct,- passing said liquefied product back through the cooler and allowing its most volatile ingredients to expand under pressure through lthe cooler,'whereby the compressed gas is cooled and the 1i ueed roducty is rendered safe for handling. 7. he method of separating out a liquefied gas from gas which consists kin first compressing said as, then cooling it in a cooler, removing t e liquefied product and causing 'it to flow back through the cooler into a container, and allowing a portion of said liquefied gas to expand against pressure while being cooled, whereby the highly volatile constituetsof said gas are. emitted to escape and the gas 'passing t rough the cooler is cooled.

8.. The method of separating out a liquefied gas, from natural gas which consists in liquefying a portion of said gas by compressing and cooling, collecting the liquid product and allowing the most volatile portionnf saidl product to expand against pressure into the intake of the compressor.

9. The method of removing liqueable constituents from crude gas which' consists in liquefying said gas in stages, .removing com ressin and cool1n 1r the as' draining g o 7 e off the liquld condensate, heating the liquid, returning, the vgasesevolved by such heating to the unliquefed gases, `cooling the liquid and draining it into a container.

11. The method of treating a liquefied product obtainedfrom any stage of a gas liquefying process, which consists in first heating the liquefied product, ,returning the gases to the unliqueied gas for another stage -of the process, then cooling the liquefied products.

lIn witnesswhereof, I hereunto subscribe aSeS t my name to this specification in the presence of two witnesses.

FRANKLIN PIERCE PETERSON. Witnesses:

. Gno. A. RoBER'rsoN,

RUTH SNYDEB. 

